Method of making tubular container bodies with solderless six-layer side seams



Dec. 14, 1948. w. McK. ART 2,455,938 METHOD OF MAKING TUBUL CONTA' R BODWITH SOLDERLESS SIX-LAYER SIDE-S EAM Filed Jan. 27. 1945 3 Sheets-Sheet1 I 'INVENTOR. WM fiz 4/01;

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4 T TOPNE Y5 Patented Dec. 14, 1948 BODIES WITH SIDE SEAMS SOLDERLESSSIX-LAYER William McK. Martin, River Forest, Ill., assignor to AmericanCan Company, New York, N. Y., a corporation of New Jersey ApplicationJanuary 27,1945, Serial No. 574,840

1 Claim. 1

The presentinventlon relates to a method of producing container or canbodies and has particular reference to forming a solderless hermeticside seam for holding the longitudinal edges of the bodies together.

An object of the invention is the provision of a method of making canbodies having side seams wherein the side seam edges of the bodies areformed with primary hooks and continuing secondary hooks and wherein aliquid lining compound is applied to one of the primary hooks so thatthe hooks may be double interfolded into a side seam of the double seamcharacter embodying at least six layers of body stock with the liningmaterial interposed between the two inner layers to produce a strongsolderle'ss and hermetic side seam for the bodies. I

Another object is the provision of such a method of making can bodieswherein the side seam hooks 'while being compressed into interfoldedrelation are confined laterally and the bodies are expanded tosimultaneously bring the bodies and their-side seams to accuratedimensions Just prior to the final compression step that locks the sideseam edges together permanently to produce the can bodies.

Numerous other objects and advantages of the invention will be apparentas it is better understood from the following description, which, takenin connection with the accompanying drawings, discloses a preferredembodiment thereof.

Referring to the drawings:

Figures 1, 2 and 3 are respectively ends views of a partially formed canbody showing various steps of forming hooks on the side seam edges ofthe body in accordance with the instant method invention;

Figs. 4, 5 and 6 are respectively sectional views of apparatus forperforming the various steps on the partially formed bodies illustratedin Figs. 1, 2 and 3, respectively, the sectional views showin the bodiesin place in the apparatus;

Fig. 7 is an enlarged sectional view of a completed side seam hook andthe apparatus used for applying a liquid lining compound to one surfaceof the hook;

Figs. 8 and 9 are respectively enlarged sectional views showingthehooked side seam portion of a partially formed can body and portions ofapparatus for compressing the interengaged edges into a side scam, theviews showing different stages of the forming of the seam and thedifferent positions of the movable parts of the apparatus;

Fig. 10 is an enlarged detail cross sectional view of the completed sideseam'of a can body made instant method invention the can bodies areproduced from rectangular flat blanks 2i (Fig. 4),

, which have been prepared previously such as by having corners or otherportions cut away or by having the blanks preformed, or by flexing,straightening or other treatments usually required before forming of theblank into tubular body shape. 7

,As the first step in the instant method, the iiat blank 2| is bent intocan body shape, with its side seam edges 22, 23 (Fig. 1) unattached,that is, separated to produce a partially formed can body 24, as bestshown in Fig. l. vFollowing the body shaping step, the marginal portionof the partially formed body adjacent its side seam edge 22 is bentinwardly along a sharp line of told 26 (Fig. 2) into -a position formingan acute angle with the body wall to produce an outer or overlookprimary hook 21. In a similar manner the side seam edge 23 is bentoutwardly to produce an inner or underlock primary hook 28.

In a subsequent step the marginal portion of the partially formed body24' adjacent the overlook primary hook 21 is again bent inwardly alon asweeping curved line of bend 29 into a position slightly less thannormal to the body wall. This produces an outer or overlook secondaryhook 3| (Fig. 3). This secondary hook is a continuation of the primaryhook 2'! and is slightly more than twice as long, as will be readilyseen in the enlarged views shown in Figs. 7 and 8. In a similar mannerthe marginal portion of the body adjacent the underlock primary hook 28is bent outwardly. This produces an inner or underlock secondary hook 32which forms a continuation of the primary hook.

Following the forming of the primary and secondary hooks on thepartially prepared can body, a liquid or fluid lining or sealingcompound 35 is applied to the inner surfaceof the underlock primary hook28, as best shown in Fig. 7. No other sealing material is applied to anyof the other surfaces of the hooks.

After thus being lined with the sealing compound 35, the overlap primaryand secondary hooks 21, 3| are interengaged with the underlock primaryand secondary hooks 28, 32 'as shown in Fig. 8, and the body is expandedto full crosssectional size. The hooks at the same time are pressedtogether into a compact inter-folded side seam 31 (Figs. 9 and 10) whichunites the side seam edges 22, 23 of the body to convert the body into acomplete tubular structure.

During this compression, the interengaged hooks are confined againstlateral displacement and the resulting side seam is accuratelydimensioned, one set of hooks closing tightly within the other. Theresult is a can body having a strong, solderless side seam of doubled,double seam character and consisting of six interfolded layershermetically sealed with lining compound interposed between the twoinnermost layers and their adjoining spaces, as best shown in Fig. 10.This broadly suggests the steps required to produce a can body having asolderless side seam in accordance with the instant method invention.

Reference will now be made to Figs. 4, 5, 6, 7, 8, 9 and 11 which showprincipal parts'of one form of apparatus for carrying out the abovemethod steps of producing the solderless side seam can body illustratedin the drawings. Shaping of the blank 21 into the cylindrical, partiallyformed can body 25 preferably is efiected by passing it endwise betweena pair of rotating rollers 8| (Fig. 4) which force it against adeflecting plate 82 disposed adjacent the rollers. The deflecting platebends or curls the blank into its open cylindrical form. A mandrel 83located above the rollers receives the shaped blank.

The edging operation for bending the marginal portions of the partiallyformed body 24 adjacent the side seam edges 22, 23 into the oppositelydirected primary hooks 21, 28, is efiected preferably by an edgingmechanism illustrated in Fig. 5. This operation isaccomplishedpreferably while the partially formed body 28 is on the mandrel 43. Thebottom of the mandrel is cut away in a recess 85 and in this recess arocker shaft d6 is mounted parallel with the mandrel. This rocker shaftis provided with a pair of edging irons 31, one located along each sideof the shaft.

The side seam edges of the partially formed body prior to edging projectdown beyond the wall of the recess in the mandrel and extend intogrooves 38 formed in the edging irons. n the outside and adjacent theside seam edges the body is held by clamps 48 which hold the edgesagainst edging steels inserted in the mandrel.

While the body is in this clamped. position, the rocker shaft 88 isoscillated first in one direction and then in the reverse direction.This movement of the rocker shaft wipes the edging irons 41 over theclamps 49 and the edging steels 5i and thus bends the body side seamedges into the overlock andthe underlock primary hooks 21, 28.

Forming of the secondary hooks 31, 32 is accomplished in a mannersimilar to that described above and while the partially formed body isstill on the mandrel 43. longitudinally along the mandrel into thedesired position. The secondary hooks are bent into shape by an edgingmechanism illustrated in Fig. 6. This mechanism includes a rocker shaft55 which is mounted parallel with the mandrel in a recess 56 formed inits lower portion. The shaft is fitted with edging irons 51 havinggrooves 58 which receive the just formed primary hooks 21, 28. Thesehooks project down beyond the inner The body may be shifted.

walls of the recess 55. Clamps 58 hold the can body against edgingsteels 6| set into the mandrel. Upon oscillation of the rocker shaft 55,the edging irons 51 wipe the hooked edges of the body against the clamps59 and the edging steels and-thus produce the overlock and underlocksecondary hoo Depositing of the lining or sealing compound 35 onto theinner surface of the underlock primary hook 28 is shown in Fig. 7. Sucha deposit prefer-v ably is effected by a liner nozzle 65 which isconnected to a suitable source of supply of the compound which may bedischarged under pressure. The nozzle is formed with an angularly shapedhead 66 having a flat outer surface and is small enough to fit into thespace between the primary hook 28 and the secondary hook 32. A dischargeaperture 61 in the flat face of the head is directly opposite the innerface of the primary hook 28 when the nozzle is in operating position.Thus the nozzle deposits 9. film of the liquid sealing compound alongthe hook in a uniformthickness. This applicationof the sealing compoundto the hook 28 is effected preferably while the can body is movinglongitudinally along the mandrel 43.

After the lining compound applying operation, the hooks 21, 28, 3|, 32are interengaged as shown in Fig. 8 and are then bumped or squeezed flatto produce the multiple layer side seam 31, illustrated in detail inFig. 10. This bumping of the side seam is done while the body is on themandrel 83 and while it is tightly clamped against the mandrel at asuitable bumping station. For this purpose there is provided a top clampbar 69 (Fig. 11) which holds the body in place and a pair of movableside wings 1!, 12 which engage the body on each side of the clamp bar.

These wings move toward the body one after the other, the wing 1! movingfirst followed by the wing 12. overlaps and interengages the body hooksand then further clamps the body against expansible side sections 15 ofthe mandrel 43. These side sections are secured by screws 16 to camblocks 11 which slide in bores 18 formed in the mandrel. The inner edgesof the cam blocks operate against a reciprocable wedge cam 18 mounted inthe mandrel, Compression springs 81 interposed between the side sections15 and the mandrel 43 press the side sections outwardly While screws 82in the mandrel limit this outward travel of the sections. The expandersections 15 are shifted outwardly from the mandrel during the seambumping operation to bring the interengaged hooks together and to expandthe body to its full and proper size.

The lower portion of the mandrel 83 carries an anvil or spline 85 (Figs.8 and 9) which is secured in an anvil block 86 inserted in the mandrel.The lower face of the anvil is formed with a rectangular shaped seamgroove 81 which in dimensions is the same size as the finished side seam31. Aseam confining bar 88 is disposd in the anvil 85 adjacent the seamgroove 81 and extends down beyond the mandrel and adjacent theinterengaged hooks of the can body. This confining bar is backed up by acompression spring 89. Ledges 9| on the upper end of the bar retain itagainst displacement from the anvil.

Bumping of the interengaged hooks 21, 28, 3|,

32 of the can body is effected by a bumping hammer 93 (Figs. 8 and 9)which is supported in a hammer block 94 carried in a vertically reciprocable hammer slide 95. The slide with the parts carried thereby isactuated in any suitable man- This movement of the wings properly ner.The bumping hammer is located below and in vertical alignment with theanvil 85. The hammer carries an upwardly projecting seam confining bar86 which extends above the hammer and which is backed up by an expansionspring 81. Ledges 98 on the lower end of the bar retain it againstdisplacement from the hammer. The inner face of the bar is in verticalalignment with the inner face of the seam groove 81 in the anvil Whenthe hammer slide 95 moves upwardly toward the anvil 85, the seamconfining bar 98 carried in the hammer 93 moves up adjacent theinterengaged books of the can body on the mandrel and thus confines thehooks between it and the cooperating seam confining bar 88 in theanvil.In this position of the confining bars, as best shown in Fig. 8, thedistance between them is the same as the width of the seam groove 81 inthe mandrel anvil. I

As the hammer 93 continues to move toward the anvil 85, the confiningbar 86 in' the hammer engages the can body wall and presses it againstthe mandrel and then remains at rest as the hammer continues to moveupwardly around it.

In a similar manner, the hammer presses the ad the primary hooks duringthe bumping of the seam, a satisfactory seam canbe made without theiruse. The main function of these expansible sections is to maintain auniform diameter in the can body.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description, and it will beapparent that various changes may be made in the steps of the processdescribed and their order'of accomplishment without departing from thespirit and scope of the invention or sacrificing all of its jacent sideof the can body against the confining bar 88 in the anvil and forcesthis bar back into the anvil. During this operation the hooks remainconfined between the confining bars 88, 96 and are progressivelycompressed into the seam groove 81 of the anvil.

By thus confining the seam during the bum ing operation, the edges ofthe primary hooks 21,-

28 are forced along the curved surfaces of the secondary hooks 8|, 32until the locking operation is completed. At the same time the excessstock of the secondary hooks is forced outwardly by the confining actionof the confining bars 88, 88 as they slide into the anvil and the hammerrespectively.

The shape of the hooked edges of the partially formed can body is suchthat when they are interengaged on the mandrel, the primary hooks areoff-center with respect to the direction of movement of the hammer 98.By this means the hooks as they are being compressed are caused torotate in a counter-clockwise direction as viewed in Fig. 8 and thisresults in wrapping the secondary hooks 8|, 82 around the primary hooks21, 28 just before the resulting seam is squeezed material advantages,the process hereinbefore described being merely a preferred embodimentthereof.

outer secondary hooks respectively constituting Jll into the seam groove81 of the anvil and bumped flat by the hammer. This double-lockingoperation is thus dependent not only on the shape or form of the hookededges of the partially 5 formed body but also on the off-center positionof the primary hooks with respect to the direction of movement of-thehammer in bumping the seam.

Although the .expansibie side sections 18 of the mandrel assist indrawing excess stock from inner continuations of said primary hooks,then applying a lining material to the inner surface of one of saidprimary hooks, then bringing the side seam edges of the tubular bodytogether to interengage the hooks of one edge with those of the otheredge, and finally compressing said interengaged hooks while confiningthe hooks against lateral displacement to-set up a.rotating action tofirst wrap the secondary hooks around the primary hooks and tothereafter flatten the wrapped hooks into an interfolded, locked sideseam including six layers of body material with thelining materialinterposed between the two innermost layers constituting said primaryhooks, whereby to produce a hermetic solderless side seam for thecontainer body.

WILLIAM McK. MARTIN.

REFERENCES CITED I The following references are of record in the file ofthis patent: UNITED. STATES PATENTS 7 Date Number Name 1,180,661 KruseApr. 25, 1916 1,526,827 Boucher Feb. 17, 1925 2,319,825 Pearson May 25,1943 FOREIGN PATENTS Number Country Date 703,725 Germany Mar. 14,1941

